High Critical Current Density of Nanostructured MgB2 Bulk Superconductor Densified by Spark Plasma Sintering

Yiteng Xing; Pierre Bernstein; Muralidhar Miryala; Jacques G Noudem

doi:10.3390/nano12152583

High Critical Current Density of Nanostructured MgB₂ Bulk Superconductor Densified by Spark Plasma Sintering

Nanomaterials (Basel). 2022 Jul 27;12(15):2583. doi: 10.3390/nano12152583.

Authors

Yiteng Xing^{1

2}, Pierre Bernstein¹, Muralidhar Miryala², Jacques G Noudem¹

Affiliations

¹ Normandie University, ENSICAEN, UNICAEN, CNRS, CRISMAT, 14000 Caen, France.
² Materials for Energy and Environmental Laboratory, Superconducting Materials Group, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan.

Abstract

In situ MgB₂ superconducting samples were prepared by using the spark plasma sintering method. The density of the obtained bulks was up to 95% of the theoretical value predicted for the material. The structural and microstructural characterizations of the samples were investigated using X-ray diffraction and SEM and correlated to their superconducting properties, in particular their critical current densities, J_c, which was measured at 20 K. Extremely high critical current densities of up to 6.75 × 10⁵ A/cm² in the self-field and above 10⁴ A/cm² at 4 T were measured at 20 K, indicating that vortex pinning is very strong. This property is mainly attributed to the sample density and MgB₂ nanograins in connection to the presence of MgO precipitates and areas rich in boron.

Keywords: MgB2; critical current density; nano grains; spark plasma sintering; superconductivity.

Grants and funding

721MA56383/Shibaura Institute of Technology (SIT) International Research Center for Green Electronics and Grant-in-Aid FD research